Operation problems and countermeasures of automatic backwash filter

Operation problems and countermeasures of automatic backwash filter

First. Composition and working principle of filter

Automatic backwashing filter is composed of tank, filter column, backwashing mechanism, electric control box, reducer, valve and differential pressure controller. The top of the tank is a backwash driving device, with a motor and a reducer. The upper part of the tank is installed with a stainless steel filter column, and the lower part is installed with a blowdown sucker and blowdown pipe.

Two inner and outer rings and multiple filter columns are installed on the diaphragm in the tank body. Clean water enters the inner cavity of the filter column through the turbidated water chamber. Impurities larger than the gap of the filter column are intercepted, and impurities accumulate, resulting in differential pressure. The debris blocked in the filter column is discharged into the sewage well, and the filter column is cleaned in turn without interruption of filtration. After washing, the sewage valve is automatically closed.

Two. Problems in operation and solutions

1. The impurities in the sludge water at the bottom of the tank are intercepted by the cracks in the filter column. Part of the water accumulates inside the filter column and the other part settles at the bottom of the tank. If the water velocity ratio in the tank is small, the impurities of large particle size and some small particle size will settle by gravity and gather at the bottom of the tank. If the water velocity is relatively high, some impurities with large particle sizes will also be suspended in the filter column.

Solution:

(1) D65mm pipe and manual ball valve are provided at the bottom of the tank. Generally, impurities with small particle size can be eliminated by regularly opening the ball valve to blow down.

(2) For large particle size impurities, you can use the direction of the drainage pipe, in the drainage ball valve outlet after the pipe to add wire buckle pipe, install valves, round steel and other tools can be inserted into the pipe or even directly to the bottom of the tank for dredging.

(3) The large pebbles, iron sheet and Angle steel in the water cannot be discharged from the sewage pipe. The valve before and after the filter can be closed, and the maintenance manhole can be opened for manual cleaning.

(4) If the above methods cannot solve the problem of blowdown, it means that the blowdown pipe is blocked, and it is necessary to open several holes in the pipe with gas cutting to dreach the pipe section by section until the pipe drains normally.

(5) Add an electric valve after the manual blowdown valve, add automatic control system such as PLC, so that the electric valve according to the water quality, regular tank bottom blowdown, can prevent the bottom of the tank silt accumulation.

(6) The pipeline shall be cleaned after construction; Daily pipe maintenance operations, waste should be cleaned up before being put into use.

2. Impurity deposition in the separator hole of the filter column The reasons for impurity deposition in the filter column are as follows:

(1) Motor and reducer failure.

(2) Transmission shaft and bearing failure.

(3) The inner shaft of the tank is broken.

(4) Clogged sewage pipe.

Solution: Repair or replace the faulty component by disassembling and separating the device to restore the cleaning function. The dredging of the outer part of the tank is ineffective, so it is necessary to dredge the pipe segment by segment with gas welding holes until the pipe drainage is normal.

The treatment method of debris deposition in the filter column: first close one of the automatic backwashing filter inlet electric valve, and pay attention to the filter before and after the change of pressure difference, if the pressure difference is not much change, or the pressure difference is large but does not affect the normal water supply, you can close the filter outlet valve, check the filter. After closing the inlet valve, open the blowdown valve to clear the debris in the filter column.

3. The differential pressure gauge is abnormal

(1) If the equipment connected with the differential pressure gauge fails, the differential pressure gauge gives wrong instructions, and backwashing is carried out continuously. The pipe at the high pressure water end of the differential pressure gauge is blocked (the blockage rate at the low pressure end is small). The number indicated by the differential pressure gauge is actually the water pressure at the low pressure end. The differential pressure gauge shows that the value has been out of tolerance, backwashing will be carried out all the time, the blowdown will not stop, and the motor is easy to burn. In this case, first check the filter inlet and outlet pressure gauge, when the number difference is inconsistent with the differential pressure gauge, should be checked step by step until the cause of the fault is found.

(2) The differential pressure gauge is damaged and should be maintained.

(3) In the northern winter, the water in the pipeline connected by the differential pressure gauge freezes, and the indicator of the differential pressure gauge is always zero. Therefore, in winter, the water pipe connected to the differential pressure gauge should be insulated to ensure that the pipeline is not frozen.

(4) In winter, the water in the drainage pipe freezes, causing the differential pressure meter to be out of tolerance, which should be dredged.

(5) winter electric valve freeze can not open, pressure difference is often. The pipeline from the bottom of the tank to the drainage well needs to be insulated to prevent freezing.

(6) Other reasons for not stopping pollution discharge. The pressure difference setting value is too small, the filter column is blocked seriously, the blowdown valve is not strict, etc., should be repaired accordingly.

The above is to share the automatic backwash filter operation problems and countermeasures, hope to be helpful to your daily use.